For internal combustion engines, such as diesel engines, nitrogen oxide (NOx) compounds and particulate matter may be emitted in the exhaust. To reduce NOx emissions, a SCR process may be implemented to convert the NOx compounds into more neutral compounds, such as diatomic nitrogen, water, or carbon dioxide, with the aid of a catalyst and a reductant. The catalyst may be included in a catalyst chamber of an exhaust system, such as that of a vehicle or power generation unit. A reductant such as anhydrous ammonia, aqueous ammonia, or urea is typically introduced into the exhaust gas flow prior to the catalyst chamber. A diesel particulate filter (DPF) can be included with the internal combustion engine, either alone or within an SCR system, to remove the particulate matter from the exhaust stream. In some instances, the DPF may be upstream of the selective catalytic reduction system, downstream of the selective catalytic reduction system or within the selective catalytic reduction system. To introduce the reductant into the exhaust gas flow for the SCR process, an SCR system may dose or otherwise introduce the reductant through a dosing module that vaporizes or sprays the reductant into an exhaust pipe of the exhaust system up-stream of the catalyst chamber. The SCR system may include one or more sensors to monitor conditions within the exhaust system.